Thanks for the quick response. Really helps a project along to have the questions answered. Will heed your advice on the bridge rectifier idea, as will have the 12 volt stepper power line to use to feed the autoreverser 5 volt regulator as an option. Many thanks.
Here is an update to my program. In the previous version I made a beginner's mistake, ie an endless loop when shortcircuit is detected. Below I inroduced a software version of a bistable multivibrator, ie when a short is detected the relay is either activated of disactivated depending on its previous state, with a 500ms delay to cover the relay response time. Additional advantage: short circuits are "immediately" detected (within a +/- 2µs response time for a 16MHz crystal frequency). //Autoreverser 1.0 (2020-12-25) // DCC Isolated Autoreversing circuit for turntable track // A0 pin connected to the out pin of the ACS712 current sensor // D2 pin connected to the gate of the MOSFET, driving the relay /* https://www.trainboard.com/highball...ller-finalised-project-proposed.154256/page-3 */ // // FILE: ACS712_20_DC.ino // Adapted from AUTHOR: Rob Tillaart // PURPOSE: demo for AutoReversing circuit for DCC turntable track polarity reversal // URL: https://github.com/RobTillaart/ACS712 // // use with Arduino Serial Plotter/Monitor #include "ACS712.h" #define relay 2 #define led 13 bool relayState = false; // Arduino UNO has 5.0 volt with a max ADC value of 1023 steps // ACS712 5A uses 185 mV per A // ACS712 20A uses 100 mV per A // ACS712 30A uses 66 mV per A ACS712 ACS(A0, 5.0, 1023, 185); // ESP 32 example (might requires resistors to step down the logic voltage) // ACS712 ACS(25, 3.3, 4095, 185); void setup() { Serial.begin(115200); while (!Serial); Serial.println(__FILE__); Serial.print("ACS712_LIB_VERSION: "); Serial.println(ACS712_LIB_VERSION); ACS.autoMidPoint(); // Serial.println(ACS.getMidPoint()); pinMode(relay, OUTPUT); pinMode(led, OUTPUT); } void loop() { int mA = abs(ACS.mA_DC()); Serial.println(mA); // comment out to increase loop speed if (mA > 1500 && relayState == false) { digitalWrite(relay, HIGH); digitalWrite(led, HIGH); relayState = true; delay(500); } else if (mA > 1500 && relayState == true) { digitalWrite(relay, LOW); digitalWrite(led, LOW); relayState = false; delay(500); } } // -- END OF FILE --
Erik, Excellent work on the autoreverser. Very happy to report the updated schematic and the revised code perform just fine with my lash up on a prototyping DIL pcb. All connected to a test track, the loco sets off the trip indicator as expected. The loco does not hesitate or stop, just continues it's travel seamlessly. I commend your time and effort, as far I'm concerned it's a project worthy of more recognition. And nicely documented on your Github if I may say. Many thanks, Bob.
Bob, this is my pleasure! It makes me thankful to have people like you appreciate my work . One thing I am hesitant about is something you made a remark to me before concerning a line of code: int mA = abs(ACS.mA_DC()); to be changed to, ..maybe? int mA = abs(ACS.mA_AC()); Just wondering if it does make a difference to performance? In a few weeks I might get the time to connect an oscilloscope to measure any speed difference in detection and relay action. But meanwhile, if you spot a difference please enlighten me .
Speaking for myself, I would be curious to know if a scope can pick a difference in performance. From what I have seen so far by naked eye, the loco has no hesitation across the gapped rails moving in both directions, my DCC-EX command does not freak out. I have a track output LED on my command station that shows a very quick short circuit, so quick it does not trip out. Would be timely to hear from other builders as to their mileage and observations. I am very happy with what we have , use it as is. I reckon Erik has burnt enough midnight oil here. Cheers
Thank you Bob, your support is very much appreciated! By the way, if you ever plan on coming to Europe just PM me . EDIT: for who is interested, my github page contains it all, https://github.com/Erik84750
Apologies, I haven't logged in for a while, and missed all the updates! If the loco is not stopping with the updated auto reverser in play and the command station not tripping, then that is fantastic! There have been changes to the time to trip in the DCC-EX software as a result of seeing auto reversers being slower than the short circuit detection, but not sure if those have progressed from our development versions into a production release yet. Either way, this is great news, and looks like a good result!
Thanks for the kind words about coming to Europe. Unfortunate for me old age and health and budget will hold me back. Would be nice to sample the famous waffles dripping with the equally famous chocolate. Now again I ask for your indulgence, referring to the autoreverser schematic, D13 of the Arduino goes to a 1k resistor then to connector marked X2-1. I assume this then goes to a LED, but connected to what / where and for indication of what activity ? To date with my test setup, I have left D13 unconnected, the autoreverser is doing it's thing but need to clarify the intent of this LED. Cheers
Erik, Referring to the actual controller code, not the autoreverser. When we see "wrong key pressed, press character key" does this mean either the asterix "*" or the hash "#" key are what the message refers to ? May seem a dumb question, but need to ask to set my use correctly. When selecting a saved position either of these "characters" must be keyed before entering the desired stored track value ? Thanks
Good morning Bob, thank you for your query. I will answer asap, but it may take a few days: we arrived yesterday evening to our Provence residence (southern France) after a +1000km drive and it will take some days before we are fully settled in.
Qualifier: while my gear has still not been set up I try to answer by reading from the code from my program; its response to "Wrong key pressed...": this appears when character (A, B, C or D) is selected, and no pending operation. When selecting B, then, after entering the numerical position value then press either # to validate, or press * to erase the last entry. When selecting D then an index value needs to be entered. When selecting # a desired index position is entered, when selecting * then the same as # except the result will be +180°. This operation is supported by character D.
Thanks for the early reply, which I will need to read over again a few times for it to sink in. My interpretation of "character" meant any keys that are not alpha or numerical, leaving the hash and asterisk as the only contenders. I do apologize if my question caused confusion, the keypad usage has been documented in your Github, and read multiple times. Some things take me a little longer lately to digest. Boolean logic I will never get so leave it alone. Back in France, long journey again, but worth every kilometer no doubt. Cheers
Hi Bob, yes indeed, our Provence home is our little paradise; we love it here. Please send me every question you have, I must admit you are an ideal tester. This helps me to improve the user experience of this project. As a creator I have a tunnel vision borne out of months of development on my own; so your testing, comments and questions are invaluable to me (an excellent example is the development of the autoreversing project; I had not thought of that before your questions on that issue ). I will modify the help file "character" issue, good to point that out. Cheers! Erik
To peteGSX, Have noticed a new throttle posted on the DCC-EX site, "blue pill wired throttle" by "n1ksn" aka Andrew Palm. Has a Github link. This has attracted my attention as a project of great interest and downloaded the available file. My apologies to raise this with you knowing it may not be politically correct, I can't see a way to make contact seeking to clarify what versions of libraries his throttle was created with ? If an update to his Github is pending, it would be welcome to see version numbers and maybe a wiring diagram to backup the pin assignments shown in the code. Currently having no luck with compiling his code, with no meaningful error messages to work with. I do acknowledge that the DCC-EX team have no obligation in this matter. Just like to see this project functional. Would be ideal if Andrew is a Trainboard member and willing to respond, but do respect his right to keep a low profile as the case may be. Thanks.
